IC cards constructed in accordance with PCMCIA (Personal Computer Memory Card International Association) standards, each have a width of 54 mm and a length of 85.6 mm, with the thickness varying for different types of such cards. The maximum thicknesses of Types I, II and IlIl cards are 3.3 mm, 5 mm, and 10.5 mm. Type II cards, which have a thickness of 5 mm, have been the most popular. Such IC cards were originally designed to store data, and standard IC cards have 68-pin connectors at their front ends for mating with host connectors at the front ends of card-receiving slots. More recent IC cards have been constructed with multi-contact rear connectors, which enable communication between an accessory such as a facsimile machine or modem, and the host, through the card. U.S. Pat. No. 5,411,402 describes one type of such rear connector, which has a row of contacts of about the same thickness as those at the front of the card, with all of such contacts having a thickness of less than 1 mm.
Communications could be established through IC cards by providing such cards with rear connectors that can accept other standard plugs, such as audio plugs. However, many common connectors such as audio plug connectors, have a thickness which approaches that of the standard thickness of 5 mm of the common Type II cards. For example, the most common audio plug connector is in the form of a cylindrical rod of 3.5 mm diameter, with ring-shaped contacts spaced along the length of the rod. Since the inside of the IC card includes a circuit board lying between top and bottom cover portions, there is not much room. Accordingly, it can be difficult to couple thick audio-type connectors to the rear of a standard IC card, especially a Type II card. An arrangement that enabled connection of such large diameter audio-type plug connectors to a thin IC card would enable even more versatile use of IC cards.